Osteoarthritis

Question 1

What is osteoarthritis?

Answer 1

Osteoarthritis is the most common type of arthritis.

=> degenerative joint disease or “wear and tear” arthritis

=> due to damage to articular cartilage

=> disease of the whole joint including subchondral bone, ligaments, capsule, synovial membrane & articular cartilage

=> major socioeconomic implication

Question 2

What are the most commonly affected areas in OA?

Answer 2

Hands, hips, and knees

Question 3

Who does it affect?

Answer 3

Women > men

> 60 years

Question 4

What is the cartilage made of?

Answer 4

Cartilage is a matrix of water (80%) and extracellular matrix i.e. type 2 collagen, aggrecan and other proteoglycans.

Question 5

OA is a spectrum:

Atrophic disease i.e. cartilage destruction to hypertrophic disease with massive osteophytes formations

Answer 5

INFO CARD

Question 6

What are the pathologies underlying osteoarthritis?

Answer 6

1. Abnormal stress / loading - mechanical cartilage damage
2. Obesity - triggers metabolic inflammation via adipokines ; risk factor esp for OA in hand & knee
3. Matrix metalloprotrinase (MMP) - matrix degradation of collagen and proteoglycans
4. Aggregase - destroys aggregans (major proteoglycan) stimulated by pro-inflammatory cytokines
5. Insulin like growth factor / TGF-beta deficiency (these growth factors involved in collagen synthesis)

Question 7

What are the predisposing factors for osteoarthritis?

Answer 7

=> Obesity

=> Hereditary

=> Gender - polyarticular OA in women > men ; higher prevalence post menopause

=> Hypermobility - increased range of joint movement and reduced stability leads to OA

=> Trauma - fracture through any joint ; meniscal & cruciate ligament tears cause OA

=> Congenital joint dysplasia

=> Joint congruity

=> Occupation i.e. miners, farmers at higher risk of OA

=> Sports - repetitive injury = higher risk of OA

Question 8

What are the causes of osteoarthritis?

Answer 8

1. Primary OA - idiopathic

2. Secondary OA : Pre-existing joint damage
=> Rheumatoid arthritis 
=> Gout
=> Spondyloarhtritis 
=> Trauma
=> Overuse e.g. sports 
=> Septic arthritis 
=> Paget's disease
=> Avascular necrosis e.g. corticosteroid therapy

3. Metabolic disease
   => Cartilage calcification
   => Hereditary haemochromatosis
   => Acromegaly
4. Systemic disease
   => Haemophilia - recurrent haemoarthritis
   => Haemoglobinopathies e.g. sickle cell disease
   => Neuropathies

Question 9

There are two main clinical subset of osteoarthritis:

i. Localised OA
ii. Primary generalised OA

What are the signs and symptoms of localised OA?

Answer 9

=> Commonly affects knee or hip joint

=> Pain and crepitus on movement

=> Background ache at rest

=> Worse with prolonged activity

=> Brief stiffness after rest ~10-15mins

=> Joints feel unstable + perceived lack of power due to pain

Question 10

There are two main clinical subset of osteoarthritis:

i. Localised OA
ii. Generalised OA

What are the signs and symptoms of generalised OA?

Answer 10

Nodal OA

=> Commonly affects distal interphalangeal joint (DIP), proximal interphalangeal joint (PIP), carpometacarpal joints (CMC) and knees in post-menopausal women

=> Joint tenderness or bone swellings

i. Herbeden’s at DIP
ii. Bouchard’s at PIP

=> Reduced range of movement

=> Mild synovitis

=> Affect on symptoms on occupation, family, hobbies, lifestyle

Question 11

What are the main signs of osteoarthritis?

Answer 11

i. Herbeden’s at DIP

ii. Bouchard’s at PIP

Question 12

What investigations are carried out for osteoarthritis?

Answer 12

Plain radiograph shows: LOSS

=> Loss of joint space

=> Osteophytes

=> Subarticular sclerosis

=> Subchondral cysts

Blood tests lack specificity - CRP may be raised

Question 13

What are the physical measures taken to manage osteoarthritis?

Answer 13

Physical measurs:

Exercise to improve local muscle strength + general aerobic fitness

Weight loss if overweight - reduces risk of OA significantly

Question 14

What is the medical management of osteoarthritis?

Answer 14

i. Regular paracetamol ± topical NSAIDs (if ineffective, use short-term codeine or oral NSAIDs +PPI)
ii. Intra-articular steroid injections temporarily relieve pain in severe symptoms if painful joint effusion present
iii. MDT approach i.e. physiotherapists, occupational health, walking aids, stretching/walking, heat or cold packs on site of pain
iv. TENS (Transcutaneous electrical nerve stimulation)

Question 15

What is the surgical management of osteoarthritis?

Answer 15

Hip or knees replacement (arthroplasty) in severe osteoarthritis